Network communication is well known. In a network, it is often desired to transmit traffic from a source node to a destination node across the network. To ensure the reliability of communication between such pairs of nodes, it is known to provide protection for communication channels.
In such a scheme, a primary connection through the network is established. A protection connection is also established taking a different path through the network. The protection connection is not, in normal use used. It only comes into action should the primary connection fail due to loss of signal, loss of continuity, increased error rate, dropped frames or so on.
A single protection connection may be dedicated to a particular primary connection (1:1 protection) or may be shared between multiple primary connections (1:n protection) depending upon how important it is that a given connection is maintained. Such protection schemes are described in the International Telecommunications Union (ITU) recommendations numbers G.808.1 and G841, the disclosures of which are hereby incorporated by reference.